The present invention relates to cartridges for storing disc-type devices. More particularly, the present invention relates to a storage cartridge which can retain a highly flexible disc such as is used for data storage in the data processing industry in such a manner as to protect this disc from damage from ambient contamination or handling. The flexible disc storage cartridge of this invention is particularly well-suited for storing so-called floppy discs in a manner which can be easily adapted to machine removal of the disc.
The use of flexible or floppy discs has become increasingly popular as a storage medium for the data processing field. Such discs have typically been applied as data entry buffers, program loaders and even as mass memories for some computer systems, particularly minicomputers. Generally, such flexible discs are fabricated from an extremely thin sheet of plastic such as Mylar which is coated with a magnetic oxide and provided with a central opening for mounting on a drive spindle. Although such discs have no substantial rigidity, they tend to initially approach a flat plane through centrifugal force when rotated at high speeds such as 900 rpm. The disc is then maintained in a relatively fixed plane such as by spinning it in proximity to a flat plate so that Bernoulli's principle becomes effective to maintain an air bearing. These discs in the past have been mounted in a cartridge with an opening through which a head can be positioned into proximity to the disc in either a contact or non-contact arrangement relative to the recording surface for reading and/or writing information on the recording surface of the disc. Since data can be retrieved from discs with significantly greater speed than tape devices, discs have been popular for storage in many computer systems.
The development of minicomputer systems have increased the demand for lower cost mass storage. Although hard disc systems could provide such storage requirements, these systems have tended to be too costly for mini-computer applications. Prior attempts to provide flexible disc drive systems which accommodate removable disc cartridges have resulted in devices which were likewise too costly and/or unreliable for use in many applications. Even though the cost of the disc medium is modest, the mechanical features and mechanisms used to implement the technology has often been prohibitively expensive. Further, reliability suffered with the removable cartridge units due to design configurations which inadequately controlled the critical tolerances required in the non-contact technology and further inadequately protected the disc surface from particle contaminants which might cause a breakdown in the air bearing separating the head and the media. The resulting relative close contact between the head and the media is sometimes referred to in the industry as head crashes and results in damage to the media and/or the head.
There has thus been a continuing need for a flexible medium disc cartridge in a low-cost configuration which, when used with an appropriate disc drive, can operate as a data storage device in a reliable and continuous manner. Further, it is important that the disc cartridge protect the disc medium from contaminants and damage during storage, shipping or handling and that the cartridge be designed to interface with a disc drive and receiver in such a way that it can be inserted into the disc drive without exposing the medium to ambient conditions or handling.